<?php
class WeixinPay
{
    protected $appid;
    protected $mch_id;
    protected $key;
    protected $openid;
    protected $out_trade_no;
    protected $body;
    protected $total_fee;
    protected $attach;
    protected $notify_url;
    function __construct($appid, $openid, $mch_id, $key, $out_trade_no, $body, $total_fee, $attach = 0, $notify_url = "http://www.weixin.qq.com/wxpay/pay.php")
    {
        $this->appid = $appid;
        $this->openid = $openid;
        $this->mch_id = $mch_id;
        $this->key = $key;
        $this->out_trade_no = $out_trade_no;
        $this->body = $body;
        $this->total_fee = $total_fee;
        $this->attach = $attach;
        $this->notify_url = $notify_url;
    }
    public function pay()
    {
        $return = $this->weixinapp();
        return $return;
    }
    private function unifiedorder()
    {
        $url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
        $parameters = array(
            "appid" => $this->appid,
            "mch_id" => $this->mch_id,
            "nonce_str" => $this->createNoncestr(),
            "body" => $this->body,
            "attach" => $this->attach,
            "out_trade_no" => $this->out_trade_no,
            "total_fee" => $this->total_fee,
            "spbill_create_ip" => $_SERVER["REMOTE_ADDR"],
            "notify_url" => $this->notify_url,
            "openid" => $this->openid,
            "trade_type" => "JSAPI"
        );
        $parameters["sign"] = $this->getSign($parameters);
        $xmlData = $this->arrayToXml($parameters);
        $return = $this->xmlToArray($this->postXmlCurl($xmlData, $url, 60));
        return $return;
    }
    private static function postXmlCurl($xml, $url, $second = 30)
    {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_TIMEOUT, $second);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($ch, CURLOPT_HEADER, FALSE);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
        curl_setopt($ch, CURLOPT_POST, TRUE);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20);
        curl_setopt($ch, CURLOPT_TIMEOUT, 40);
        set_time_limit(0);
        $data = curl_exec($ch);
        if ($data) {
            curl_close($ch);
            return $data;
        } else {
            $error = curl_errno($ch);
            curl_close($ch);
            throw new WxPayException("curl出错，错误码:{$error}");
        }
    }
    private function arrayToXml($arr)
    {
        $xml = "<root>";
        foreach ($arr as $key => $val) {
            if (is_array($val)) {
                $xml .= "<" . $key . ">" . arrayToXml($val) . "</" . $key . ">";
            } else {
                $xml .= "<" . $key . ">" . $val . "</" . $key . ">";
            }
        }
        $xml .= "</root>";
        return $xml;
    }
    private function xmlToArray($xml)
    {

        libxml_disable_entity_loader(true);
        $xmlstring = simplexml_load_string($xml, "SimpleXMLElement", LIBXML_NOCDATA);
        $val = json_decode(json_encode($xmlstring), true);
        if ($val['result_code'] == 'FAIL'){
            return_msg(-1,$val['err_code_des'],[]);
        }
        return $val;
    }
    private function weixinapp()
    {
        $unifiedorder = $this->unifiedorder();
        $parameters = array("appId" => $this->appid, "timeStamp" => '' . time() . '', "nonceStr" => $this->createNoncestr(), "package" => "prepay_id=" . $unifiedorder["prepay_id"], "signType" => "MD5");
        if (!isset($unifiedorder["prepay_id"])){
            return_msg(-1,$unifiedorder['return_msg']);
        }
        $parameters["paySign"] = $this->getSign($parameters);
        $parameters["prepay_id"] = $unifiedorder["prepay_id"];
        return $parameters;
    }
    private function createNoncestr($length = 32)
    {
        $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
        $str = '';
        $i = 0;
        while ($i < $length) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
            $i++;
        }
        return $str;
    }
    private function getSign($Obj)
    {
        foreach ($Obj as $k => $v) {
            $Parameters[$k] = $v;
        }
        ksort($Parameters);
        $String = $this->formatBizQueryParaMap($Parameters, false);
        $String = $String . "&key=" . $this->key;
        $String = md5($String);
        $result_ = strtoupper($String);
        return $result_;
    }
    private function formatBizQueryParaMap($paraMap, $urlencode)
    {
        $buff = '';
        ksort($paraMap);
        foreach ($paraMap as $k => $v) {
            if ($urlencode) {
                $v = urlencode($v);
            }
            $buff .= $k . "=" . $v . "&";
        }
        $reqPar;
        if (strlen($buff) > 0) {
            $reqPar = substr($buff, 0, strlen($buff) - 1);
        }
        return $reqPar;
    }
}